Most people only know about red raspberries, but there are also black and yellow ones too, and now researchers are testing whether the three of them can make delicious jellies and jams. (Photo: Quinn.Anya, CC BY-SA 2.0)

Who doesn't love raspberries? Sweet with a subtle tang, these delicious fruits just melt in your mouth. An eternal favorite, raspberry jam is generally made with red raspberries. But a new study in the Journal of Food Science, conducted by the Institute of Food Technologists (IFT), found that producing a mixed-raspberry jelly, with black and yellow raspberries, could be a good alternative to a single-colored jelly.

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The goodness of raspberries cannot be extolled enough. They are a powerhouse of nutrients and antioxidants, including vitamin C, manganese, copper, and iron, meaning that too much can never be enough. Traditionally, red raspberries have been used to make jams, jellies, and juices. They have a short shelf-life and making them into preserves is a more economically viable option. But other varieties such as yellow and black raspberries also have the same health benefits. Yellow raspberries, like the red ones, are rich in carotenoids, while black raspberries are rich in ellagic acid and anthocyanins.

Hence, researchers in Brazil are trying to incorporate yellow and black raspberries into red raspberry jellies. Apart from being healthy, the berries are also easy to cultivate, and offer better productivity and quality.

For their study, researchers tried to assess the processing potential of yellow and black raspberries in the preparation of jellies through mixture design and response surface methodology (RSM). In other words, they tested which combination of each raspberry worked best. They used three varieties of raspberries: yellow (Golden Bliss cultivar, Rubus idaeus), black (Rubus niveus), and red (Batum cultivar, Rubus idaeus).

They evaluated the mixtures based on sight, smell, touch, and taste, and found that a mixture of red, black, and yellow raspberries could make a commercially viable product. The mixture of berries they agreed on was one with zero to 30 percent yellow berries, 25 to 50 percent black raspberries, and 30 to 75 percent red raspberries.

There hasn't been much research into the feasibility of using black and yellow raspberries in preserves. But with this study, raspberry growers may be encouraged to cultivate raspberries other than red for use in jams and jellies.